1. Field of the Invention
The present invention relates generally to an electronic selection panel having touch-actuated capacitive switches and, more particularly, pertains to a selection panel wherein each capacitive actuated switch is transparent and includes a changeable display card positioned behind the selection panel.
2. Disscussion of the Prior Art
Switching panels are well known in the art for a variety of machines and appliances such as electric ranges, microwave ovens, washing and drying machines, elevators, vending machines, or the like. Known types of switching panels frequently have incorporated therein mechanical pushbutton type switches and, more recently, have utilized touch-actuated capacitive switches which rely not upon a mechanical movement in the switch but rather upon a change of capacitance which is produced when a conductive body such as a users finger is pressed against one plate of the capacitor. Frequently the function of a particular switch is indicated by a permanent indicia, such as a permanent overlay, embossed or engraved markings, provided either directly on the switch face or being closely associated therewith on the switching panel. Unfortunately, the permanent indicia often do not offer a desired flexibility for the switching panel which would allow replacement of the indicia either to indicate a different switch function or to allow the replacement of a particular design or color.
Furthermore, the advent of electronic controls for many appliances has also produced a requirement or need for a simple method of entering information into the controls. Heretofore, a keyboard has fulfilled this function by allowing a user to enter information by depressing a series of push button switches. However, the keyboard is not entirely desirable or suitable in many instances, especially in connection with appliances, because water and other foreign matter can readily collect on the surface of the keyboard as well as enter the interior thereof. In order to overcome problems associated with mechanical keyboards, there have been developed electronic keyboards, sometimes known as "touch plates". A touch plate is generally sectioned off into a plurality of areas, each such area representing certain information which is to be entered into the control by the touching of that particular area.
Jordan U.S. Pat. No. 4,056,699 and Castleberry et al U.S. Pat. No. 4,161,766 each disclose typical touch-actuated capacitive switching panels. Jordan discloses a touch plate assembly having a legend applied over the top electrically conductive coating forming one plate of the parallel plate capacitor switch to indicate the switching function thereof. Castleberry et al. illustrates a typical touch-type capacitive switching pad, but does not particularly specify the nature of the indicia associated with the pad.
Harris U.S. Pat. No. 3,777,222 discloses a modular touch sensitive indicating panel having an overlay which features protectively encapsulated and customized art work of characters therein. The elastic overlay membrane forms a covering surface for the panel with discrete switch sites therein being designated by the integral art work. The touch sensitive switches of this reference are not capacitive type of switches.
Lauren et al. U.S. Pat. No. 3,188,437 discloses a push button signal light switch having a removable indicia element therein. A switch such as an elevator push button switch has a translucent base portion with an associated indicia element. The switch is designed with a removable indicia element to allow the element to be easily replaced by indicia of a variety of designs or colors.